Study on tensile properties of Z ‐pin reinforced bismaleimide resin matrix composites with single lap joints

Abstract The objective of this study is to examine the influence of Z‐pin implantation parameters on the load‐bearing effectiveness of single lap joints reinforced with Z‐pins. This study explores the effect of Z‐pin implantation parameters on the load‐bearing performance of the joint. Concurrently, a finite element simulation is employed to conduct a comprehensive analysis of the stress distribution and failure mode of the joint throughout the damage process. Furthermore, high‐temperature tensile tests were conducted to evaluate the impact of temperature on the Z‐pin reinforcement mechanism. The findings demonstrated that Z‐pin reinforcement markedly augmented the peel resistance at the joint extremities, thereby postponing the inception of fissures. The maximum shear stress at the joint end exhibited a 4.81‐fold increase. During the loading process, the presence of Z‐pins effectively impeded the propagation of cracks, thereby enhancing the load‐carrying capacity of the joint. The reinforcement effect of Z‐pins exhibited variability with respect to the implantation area, with a maximum increase of 41.6%. The load capacity of the joint reached 2.51 kN/g per unit mass. However, as the temperature increased, Z‐pin pull‐out occurred, leading to a reduction in reinforcement efficiency. At high temperatures, frictional forces during Z‐pin pull‐out became the primary mechanism for dissipating crack propagation energy. These findings provide valuable insights into optimizing Z‐pin reinforcement strategies for enhancing the mechanical performance of composite joints, particularly under varying thermal conditions. Highlights The efficiency of different pin positions was evaluated. Evaluation of Z‐pin enhancement efficiency using joint loading efficiency. Establishment of a high‐precision finite element model with Z‐pin. Analyzed the damage process of joints at high and normal temperatures. Study the failure form of Z‐pin at high temperature.